The present invention relates to an ink jet recording apparatus employing inks in which pigments are used as coloring agents and to a flushing process for the ink jet recording apparatus. More particularly, the invention relates to an ink jet recording apparatus for flushing dark pigment inks and light pigment inks onto flushing portions (boxes) and a flushing process for the ink jet recording apparatus.
As the ink jet recording apparatus in the background art, there is an apparatus that performs the flushing. In such apparatus, the flushing is performed every color at respective positions pursuant to the alignment of head nozzles.
The ink jet recording apparatus is constructed, for example, as shown in JP-A-8-169155 (FIG. 4).
Here, pigment inks 104 (a black ink 104A and color inks 104B to 104G) are provided to a recording head 101. As shown in FIG. 5, the color inks 104B to 104G include dark/light cyan inks 104B, 104C, dark/light magenta inks 104D, 104E, and dark/light yellow inks 104F, 104G.
These inks 104A to 104G are ejected from respective nozzles 103 (103A, 103B, 103C, 103D, 103E, 103F, 103G) of the recording head 101.
Meanwhile, in order to prevent the clogging of respective nozzles 103A to 103G of the recording head 101, as shown in FIG. 5, the recording head 101 is caused to move to a flushing box position on the outside of a left end edge 102A of a recording paper 102, for example, every time when the recording head 101 performs the reciprocating movement several times (4 to 5 times) along a main scanning direction indicated by the arrow A, and then the inks 104A to 104G are caused to eject (flush) from respective nozzles 103A to 103G.
The flushed inks 104A to 104G are allowed to penetrate into flushing portions (boxes) of a platen 105.
However, in the case where inks using pigments as the coloring agents are employed, a moisture contained in the inks 104A to 104G evaporates to start precipitation of the pigment solid components of the inks 104A to 104G, depending on the operating circumstances of the ink jet recording apparatus, particularly by a room temperature rise caused, for example, in the summer season.
In particular, weight percents of pigment solid components in the dark pigment inks 104B, 104D, 104F of cyan, magenta and yellow are higher rather than the light pigment inks 104C, 104E, 104G. The concentrations of the pigment solid components in the light pigment inks are xc2xd or less of the dark pigment inks in terms of weight %.
For this reason, as shown in FIG. 5, in some cases the dark pigment inks 104B, 104D, 104F of cyan, magenta and yellow cannot penetrate sufficiently into the flushing portions (boxes) of the platen 105. Thus, the pigment solid components of the dark pigment inks 104B, 104D, 104F of cyan, magenta and yellow are deposited on the surface of the platen 105 as the so-called piled-up sediment 106.
In this manner, once the piled-up sediment 106 is generated on the surface of the platen 105, the deposition proceeds. At a certain time when the recording head 101 comes to the flushing position, such piled-up sediment 106 rubs nozzle surfaces of the recording head 101 to cause the defective ejection.
The present invention has been made in view of the above problems, and it is an object of the present invention to provide an ink jet recording apparatus and a flushing process capable of allowing flushed dark inks to sufficiently penetrate into a platen when inks that use pigments as coloring agents are employed.
Other objects and effects of the invention will become apparent from the following description.
In order to achieve the above object, the present invention provides an ink jet recording apparatus that moves a recording head along a guide shaft to flush inks to flushing portions of a platen when employing inks using pigments as coloring agents, the ink jet recording apparatus having a feature that the recording head performs a first flushing for flushing one of dark pigment ink(s) and light pigment ink(s) and a second flushing for flushing the other of the dark pigment ink(s) and the light pigment ink(s) onto the same position(s) of the platen.
Also, the present invention provides a flushing process for an ink jet recording apparatus that employs inks using pigments as coloring agents and moves a recording head along a guide shaft to flush the inks to flushing portions of a platen, the flushing process having a feature that a first flushing for flushing one of dark pigment ink(s) and light pigment ink(s) and a second flushing for flushing the other of the dark pigment ink(s) and the light pigment ink(s) are performed onto the same position(s) of the platen.
Here, the first flushing and the second flushing may be carried out as follows: the dark pigment ink is firstly flushed, followed by the flushing of light pigment ink to cover the flushed dark pigment ink, or alternatively, the light pigment ink is firstly flushed, followed by the flushing of dark pigment ink to cover the flushed light pigment ink. In short, to implement the present invention, the order of flushing of the dark pigment ink and the light pigment ink may be set arbitrarily and selected appropriately.
Also, as the first flushing and the second flushing, it is not necessary to flush the dark pigment ink and the light pigment ink alternately by the same times. Specifically, the light pigment ink may be flushed several times after the dark pigment ink is flushed only once, or the dark pigment ink may be flushed several times after the light pigment ink is flushed only once.
In addition, if the black ink and the color inks are employed, the dark pigment ink and the light pigment ink in the present invention do not necessarily have the same hue mutually. For example, the dark pigment ink of cyan and the light pigment ink of yellow may be flushed onto the same position of the platen in any order.
In the ink jet recording apparatus and the flushing process for the ink jet recording apparatus that are constructed in this manner and employ the inks using the pigments as the coloring agents, the first flushing for flushing one of the dark pigment ink(s) and the light pigment ink(s) and the second flushing for flushing the other of the dark pigment ink(s) and the light pigment ink(s) are performed onto the same position(s) of the platen.
The weight percents of the pigments in the light pigment inks are lower than those in the dark pigment inks. Therefore, for example, in the case that the light pigment ink is to be flushed after the dark pigment ink is flushed, the solvent components constituting the light pigment ink prevent further deposition of the pigment solid components of the dark pigment ink as the piled-up sediment. The dark pigment ink deposited as the piled-up sediment and the light pigment ink are mixed, making it possible to penetrate both together into the flushing portion (box) of the platen.
On the contrary, for example, in the case that the dark pigment ink is to be flushed after the light pigment ink is flushed, the dark pigment ink is mixed with the solvent components constituting the light pigment ink previously penetrated into the flushing position of the platen. Thereby, not only the precipitation of the pigment solid components in the dark pigment inks on the platen can be suppressed, but also the dark pigment ink can be allowed to penetrate into the flushing portion (box) of the platen. As a result, the deposition of the dark pigment inks on the surface of the flushing portions (boxes) as the piled-up sediments can be prevented.